Pursuing the ‘Holy Grails’ of Battery Tech

It’s been a pretty impressive year for energy storage. Batteries are getting cheaper, there was a huge jump in grid-scale installs, and there are several promising breakthroughs in new technologies. That’s all exciting news for some of the big name companies and clean energy investors lured into the multibillion-dollar market.

Last year, U.S. energy storage capacity grew to 580 megawatts, with 221 megawatts worth of installations, more than triple the amount added in 2014. While home energy storage systems are getting a lot of buzz, about 85 percent of this new capacity actually came from utility-scale installations.

And at the heart of energy storage systems are batteries, most using the same lithium-ion technology that powers your cell phone, laptop or electric car.
In large-scale energy storage, lithium-ion batteries will probably continue to be the dominant technology for at least a few more years, since they have the easiest pathway for scaling up. Batteries are also getting more affordable – costing about half what they did five or six years ago.

Why Utilities Need Energy Storage
Batteries provide a better connection between renewables and the grid. The natural intermittency of wind and solar means they can’t deliver the on-demand power needed for grid operation. Flexible, large-scale storage allows the utilities to take that intermittent power generation and store it, dispatching the energy as needed, rather than when it’s generated.

Solar panels, for example, begin generating electricity at dawn, increase production until a midday peak, and then produce less through the afternoon until sunset. You can’t control when that energy is generated, but if you store that energy, you can control its distribution.

ARPA-E And Their ‘Moonshots’
Advanced Research Projects Agency-Energy (ARPA-E), part of the Department of Energy, claims to have made major advances on batteries that could make electric cars and renewable energy cheaper. The agency funds early-stage research in energy generation and storage. ARPA-E projects (sometimes fondly called “moonshots”) were considered too risky for private-sector investment but could possibly lead to some real breakthroughs in technology. ARPA-E fosters all sorts of different technologies, but large-scale energy storage is the area that is “delivering big time” for the agency.

“We’ve reached some holy grails in batteries,” ARPA-E’s director Ellen Williams told The Guardian. “Just in the sense of demonstrating that we can create a totally new approach to battery technology, make it work, make it commercially viable, and then get it out there.”

“Our battery teams have developed new approaches to grid-scale batteries and moved them out,” Williams said. “Three companies now have batteries on the market, selling grid-scale and backup batteries. Half a dozen other companies are developing new batteries.”

Williams said that the agency has helped launch a dozen high-risk projects based on new technologies that could outperform current batteries in the market. While the agency did not release specific details, it said it has achieved several breakthroughs in energy-storage technology that could transform the U.S. electrical grid in the next five to 10 years.

The Next-Gen Technologies
“The companies incubated at ARPA-E have developed new designs and new chemistries for batteries, which are rapidly bringing down the costs of energy storage,” Williams said.

A team at the Massachusetts Institute of Technology is developing a community-scaled battery that contains liquid-metal electrodes and a molten-salt electrolyte. Because metals and salt don’t mix, the three liquids of different densities naturally separate into layers, eliminating the need for a solid separator. This design significantly reduces packaging materials and allows more space for storing energy.

A Harvard University project is working on a grid-scale, organic flow battery to store electricity from renewable sources. Flow batteries store energy in external tanks instead of within the battery container, permitting larger amounts of stored energy at lower cost per kWh. Harvard’s organic flow battery design could hold up to 10 times more energy by volume compared to other flow batteries.

Targeting the electric vehicle market, a Stanford University project is working on an all-electron battery that stores energy by moving electrons rather than ions. They say a new structural design increases the amount of energy the battery can store while reducing degradation.

A Case Western Reserve University team is working on a water-based, all-iron, organic flow battery for grid-scale energy storage at lower cost per kWh.
PolyPlus is developing a lithium-air battery that they say can store nearly seven times more energy than lithium-ion batteries, allowing electric cars to travel 500 miles on a single charge.

Over the past seven years, ARPA-E has invested about $1.3 billion across 475 projects, 45 of them have now secured more than $1.25 billion in private sector funding.

Growth And Investment
There’s a multibillion-dollar race to build the next-generation of energy storage. Utility-scale grid storage is set to reach up to 12 gigawatts by 2024, while revenues are projected to grow to around $8.4 billion annually. Worldwide, energy storage could reach 240 gigawatts by 2030, according to a report by Citigroup.